In modern farm operations in many rural areas each farm comprises a number of more or less widely separated fields to be worked, rather than a single large field, and it is necessary not only to draw implements such as seeders across the fields, but also to transport the implements from field to field, frequently by the use of public highways.
It is generally well-known that modern farm tractors are sufficiently powered to enable the use of a plurality of implements in side-by-side field operations, thus reducing the number of passes needed to cover a field of given width and so increasing the time-effectiveness of the farming operation. Such a multiple implement arrangement, however, is usually too wide to pass through farm gates, or to be transported on the public roads, the traffic lanes of which are frequently not much wider than a single implement. Wideness of his gates is within a farmer's control, but he may not block the full width of a public road in moving his equipment from one field to another.
The time and effort involved in disconnecting implements from a tractor, transporting them separately from field to field, and recoupling them at the new location are significant.
Attempts to relieve this situation have taken advantage of the fact that implements are frequently shorter than they are wide. One expedient has involved loading the coupled implement sideways on a long trailer, transferring the tractor to the end of the trailer, and drawing the latter endwise along the road. Another expedient has involved providing the combined implements with auxiliary wheels, orthogonal to the working wheels, which can be lowered to lift at least some of the latter from the ground, and recoupling the tractor to the end of the assembly instead of to the sides thereof. These arrangements limit the front-to-back dimension of the implements being transported.